Allo allo allo!
I'm Blocky McBlockface and I patrol the web defending you and your kids from poisoned cookies the baddies keep laying about.
The web is full of creeps that want to follow you around gathering more data on you than you'd care for. Unauthorized cookies are planted through third-party sites and embedded within legitimate content.
Blocking all third-party cookies means you won't be able to functionally use some websites. That's where I step in to figure out the goodies from the baddies.